Vibrato producing loud speaker



April 15, 1958 E. D. TElKOWSKl 2,831,051

VIBRATO PRODUCING LOUD SPEAKER Filed Oct. 5, 1953 2 Sheets-5heet lJNVENTOR.

C nal era D /Eiiau/xli J l/wwey "Wm 1W- April 15, 1958 E. D. TEIKOWSKIVIBRATO PRODUCING LOUD SPEAKER Filed Oct. 5. 1953 2 Sheets-Sheet 2 h V 5mw m A, ha Z w W W 1 4 m w I w W 4 w m 7 WY 3 a 62 a 6 2 2 3 6 2 q a 3 ra United States Patent "IBRATO PRODUCING LOUD SPEAKER Edward D.Teikowski, Milwaukee, Wis. Application October 5,1953, Serial No. 38337611 Claims. (Cl. 179-1) This invention relates generally to loud speakersand more particularly to an improved loud speaker mounting for imposinga vibrato effect upon the reproduced sound.

Tone qualities may be substantially improved and rendered more pleasingby imposing'a vibrato effect upon the sound, and-for this reasonmanymeans have been devised for producing the vibrato efiect. It may beproduced mechanically by reproducing the sound in a loud speaker, androtating the speaker or directing the sound from it into a rotatinghorn. Such an arrangement imposes the vibrato effect upon the sound torender it much more pleasing to the senses. Howevenfor maximum tonequality, it has been found necessary to transmit the sound to twospeakers, one a high frequency speaker and the other a low frequencyspeaker, and rotate both of the speakers or direct the sound emanatingtherefrom into suitable rotating horns. This requires a cumbersome andexpensive apparatus.

it is therefore a general object of the present invention. to provide animproved loud speaker mounting for producinga vibrato effect upon thesound being reproduced.

Another object of thepresent invention is to provide an improved loudspeaker mounting for producing a vibrato eifect of maximum quality onthe sound being reproduced while utilizing only one loud speaker.

Another object is to provide a loud speaker system which improves thetone quality of the sound being reproduced.

Another object is to provide a rotating loud speaker mounted in aresonator for improving the tone quality of the sound being reproduced.

Another object is to provide an improved resonator for use with a loudspeaker to improve the tone quality of the sound being reproduced by theloud speaker.

Another object is to provide a loud speaker system in which the soundbeing reproduced is distributed evenly over a wide area.

A further object is to provide an improved loud speakor mounting forproducing a vibrato effect upon sound which is efficient in operationbut of sturdy and simple construction.

According to this invention the improved loud speaker mounting comprisesa cabinet having two bearings fixed therein for rotatably supporting avertical shaft. The shaft in turn carried two oppositely disposed loudspeakers, only one of which is operated at any one time for reproducingsound, the other serving as a spare speaker as Well as to balance theshaft'for smooth rotation. The shaft is rotated by an electric motorwhile the loud spealo er is reproducing sound to. produce a vibratoeffect upon the sound. The speaker is connected to astandard amplitierthrough the bearings which. areelectrically conductive for transmittingthe current .to the shaft which is connected tothe speakercoil tooperatein the manner-of a slip ring connection. The resonant mounting.of the speaker includes a metal cowl completely surrounding thespeaker,. with .a flanged .disk.;supported concentrically withthe cowlto the rear of the speaker and spaced slight- ZhdBLllSl ly from the rearopening of the cowl. This arrangement has been found to enhance the tonequality of the sound being reproduced by the loud speaker to a muchgreater degree than the same sound would have if reproduced by arotating loudspeaker without the resonant mounting.

The foregoing and other objects of this invention, which will becomemore fully apparent from the following de tailed description of anembodiment thereof, may be achieved by the apparatus herein described byway of example, in connection with the illustrations of its structuralcomponents in the accompanying drawings, in which:

Figure l is a perspective view of a cabinet housing the loud speakermounting comprising the present invention;

Figure 2 is a plan view of the aparatus illustrated in Figure 1 with thecabinet top partially cut away to reveal the interior mechanism;

Figure 3 is a view partly in front elevation and partly in verticalsection taken substantially along the plane represented by the line 33in Figure 2; and,

Figure is a fragmentary detail view in verticalsection depicting theconstruction of the upper bearing for supporting the shaft carrying theloud speakers.

Referring more specifically to the drawings and particularly to Figure 1thereof, Where there is shown a cabi net 5 of a type suitable forhousing the loud speaker arrangement comprising the present invention.An octagonally shaped cabinet is illustrated as a suitableconfiguration, although it is to be understood that the cabinet maybeconstructed in any desirable shape suitable for enclosing and supportingthe loud speaker mounting of the present invention.

In the illustrated embodiment, each of the eight sides of the cabinet 5isflprovided with a centrally located opening .6 through which the soundemanating from the loud spea.:er within is emitted. The openings 6 arecovered with a relatively coarse mesh fabric which wil not undulyinterfere with the passage of sound, the fabric covering being providedfor=the sake of appearance only. Two of the sides of the cabinet 5 aresupported by hinges 7 so that they will serve as doors 8 for gainingaccess to the mechanism housed within the cabinet.

As clearly shown in Figure 3, the interior of the cabinet Sis providedwith two bearings 12 and 13 for rotatably supporting a vertical shaftThe bearing 12 is centrally secured to the top of the cabinet 5 whilethe bearing 13 is similarly fixed to the bottom of the cabinet. Thelower bearing 13 comprises a cylindrical portion 15 having a flange 16formed integrally therewith for receiving screws 17 which secure thebearing to the floor of the cabinet 5. A cone shaped recess is form thetop of the cylindrical. portion 5 for receiving a complementarytaperedend 1-9-formed on the lower end of the shaft 14. Thus the shaft 14 isfirmly supported against lateral movement but is free torotate withinthe conical recess 18.

The upper-encirof the shaft 14 is similarly supported by the bearing 12which is constructed to facilitate the assembly and removal of the shaft14 as clearly shown in Figure 4-. The bearing 12 includes a cylindricalportion 23=having a fiange 24 for receiving screws 25 which are screwedinto the top of the cabinet 5 to securethe bearing in position. In thisinstance, however, the cylindrical portion 23 is not formed to provide abearing surface for the shaft 14 as in the lower bearing 13, butinstead'is'provided with a concentric bore 26 for receiving a coilspring 27 and a plug 23 slidably mounted therein.

TheplugZSis urgedoutwardly of thebore 26 by the spring 23, and itsexposed end is formed to present a conical recess 32 similar to theconical recess 18 of the lower bearing 13. However, in this instance,the shaft 14 is not in direct engagement with the recess 32, but

is provided with an adapter 33 having a tapered end 34 complementary tothe recess 32 for engagement therewith to rotatably support the upperend of the shaft 14. The adapter 33 is rigidly secured to the upper endof the shaft 14 to rotate with it, the end of the shaft being disposedwithin a bore 35 formed axially in the end of the adapter 33 oppositethe tapered end 34. However, the shaft 14 is electrically insulated fromthe adapter 33 by an insulating material 36 lining the bore 35 forreasons to be subsequently described.

The spring 27 functions to yieldably urge the plug 28 into engagementwith the adapter 33 to firmly support the shaft 14 against lateraldisplacement but leaves it free to rotate. To remove the shaft 14 fromits supporting bearings 12 and 13, it is only necessary to raise itagainst the pressure of the spring 27 to disengage the tapered end 19from the recess 18 and displace the its removal. On the other hand, toreplace it, it is only necessary to engage the tapered end 34 of theadapter 33 with the recess 32 and force the plug 28 upwardly against thepressure of the spring 27 to permit the tapered end 19 to be moved intoengagement with the conical recess 13. The shaft 14 may then be releasedand the downward pressure of the spring 27 will serve to securely retainthe shaft 14 and its adapter 32 within the recesses 18 and 32respectively.

Two cone type loud speakers 40 are rigidly secured to the shaft 14 inopposed relationship to rotate with it for producing the vibrato effect,the speakers being disposed within a resonator mounting for enhancingthe quality of the tone, and generally identified in the drawings by thereference numeral 41. The two speakers 46 and their resonant mounting 41are identical in construction and therefore only one of them will bereferred to, which will serve to describe both of them. In Figure 3 oneof the speaker assemblies is shown in side elevation and a sectionalview of the other is shown to illustrate the details of construction.

As there shown, the speaker 40 is disposed within the resonator mounting41 comprising a cowl 42 of cylindrical shape for enclosing andsupporting the speaker 40. The forward end of the cowl 42 is bentinwardly to form an inwardly extending flange 43 to which a peripheralflange 44 of the cone of the speaker 40 is secured for rigidlysupporting the speaker within the cowl 42.

The rear end of the cowl 42 is bent outwardly to form an outwardlyextending flange 48 through which the cowl 42 is attached to a disc 49in spaced relationship by means of rivets 50 passing through spacers 51.The spacers serve to position the disc 49 a slight distance from therear opening of the cowl 42. The disc 49 is shaped to form a flange 52extending forwardly over the cowl 42 a slight distance from theperiphery of the flange 48 to provide an annular space 53 for thepassage of sound reflected from the disc 49. Thus, the cowl 42 and thedisc 49 combine in the particular disclosed arrangement to form theresonator 41 for enhancing the quality of the sound, which is emittedfrom the forward opening of the cowl 42 as well as from its rearwardopening through the annular space 53.

The two speaker assemblies are supported on the shaft 14 by a pair ofbrackets 56, each comprising a sleeve 57 fixed to the shaft 14 by a setscrew 58. A channel member 59 is secured to the sleeve 57 and itsextending legs 60 are each attached to one of the discs 49 to therebysupport the two speaker assemblies on the shaft 14 in opposedrelationship to rotate with the shaft. 7

Although two speaker assemblies are illustrated in the drawings, theyare utilized individually, the other serving as a spare speakerconveniently available for immediate shaft laterally to free it from thebearings and permit use in the event of a failure of the other. Inaddition, it serves to balance the shaft for smooth and even rotation,eliminating the necessity of ballast to balance the overhanging weightof the other speaker.

The speaker 40 is energized by a standard amplifier indicateddiagrammatically in Figure 3 and identified by the reference numeral 64.The sound is received by the amplifier 64 from its source through astandard microphone (not shown) and transmitted to the speaker 5-5) by apair of conductors 65 and 66. The conductor is connected to the upperbearing 12 while the conductor 66 is connected to the lower bearing 13.

Since the bearing i2 is electrically conductive and has metal to. metalcontact with the adapter 33, the electric current travels from thebearing 12 to the adapter 33. A conductor 67 is connected to the adapter33 and carries the current to a plug 68, the current being pre ventedfrom entering the shaft 14 from the adapter 33 by reason of theelectrical insulation 36 separating the adapter from the shaft.

As previously stated, each of the two speaker assemblies are identicalin construction, and therefore both are provided with a jack 72 adaptedto receive the plug 68 and carry the current therefrom for energizingthe speaker. With this arrangement the plug 68 may be inserted intoeither one of the two jacks 72 to connect either one of the two speakers49 with the amplifier 64. However, since only one plug 68 is provided,only one speaker at a time can be connected, and either one may beselected with a minimum of efiort, simply by transferring the plug 68from one of the jacks 72 to the other.

From the jack 72 the current is carried to the speaker 40 by a conductor73. The path of the current then continues from the speaker 40 through aconductor 74 to the shaft 14 which is separated from the other part ofthe circuit by the insulation 36 as previously described. Here again, byreason of the metal to metal contact with hearing 13, the current passesfrom the shaft 14 to the bearing 13, and thence is carried back to theamplifier 64 by the conductor 66 to complete the circuit. Thus, thespecific bearing arrangement shown is particularly adaptable for thepresent application in that the bearings 12 and 13 efiiciently supportthe shaft 14 and its associated speakers for rotational movement, andalso serve to carry the energizing current to the rotating speakers.

In order to impose the pleasant vibrato effect on the sound emanatingfrom the speakers 40 it is necessary to rotate the speakers while thesound is being reproduced as previously stated. Power for rotating theshaft 14 with its speakers 40 and their resonator mounting 41 isobtained from an electric motor 77. A vibration absorbing mounting 78 isprovided for supporting the motor 77 on the floor of the cabinet 15 toeliminate any adverse effects on the speakers 41) from any vibrationwhich may be created by the motor 77 when energized.

A pulley 79 is keyed to the drive shaft of the motor 77, and a similarpulley 80 is fixed to the shaft 14. The power from the motor 77 istransmitted to the shaft 14 by a V-belt 81 interconnecting the twopulleys 79 and 80. Thus, rotation of the speakers 40 is effected byenergization of the motor 77 to produce the pleasant vibrato effect onthe sound reproduced by the speakers 40, which is further enhanced bythe resonator mounting 41.

From the foregoing description of the construction and operation of apractical embodiment of the improved vibrato producing loud speakerprovided by the present invention, it will be apparent that theapparatus is especially adapted to improve the tone quality of soundreproduced by the energized speaker by reason of the combined effect ofthe rotational movement of the speaker with the resonator mounting inwhich the speaker is supported.

Although the illustrative embodiment of the invention assnosi has beendescribed in considerable detail for the purpose of setting forth anoperative and practical exemplifying structure, it is to be understoodthat the structure shown and described is intended to be illustrativeonly, and that various characteristics of the invention may beincorporated in other structural forms without departing from the spiritand scope of the invention as defined in the subjoined claims.

The principles of the invention having now been fully explained inconnection with the foregoing description of embodying structure, Ihereby claim as my invention:

1. In an apparatus for enhancing the tone quality of reproduced sound, acabinet, a shaft rotatably mounted in said cabinet, a pair of resonatormountings supported on said shaft in opposed relationship to rotate withit, a speaker supported within each of said resonator mountings so thatthe tone of the sound emanating from said speakers is enhanced by hesympathetic vibration of said resonator mountings, and an amplifierconnectible to either one of said speakers selectively for individualenergization, whereby the tone quality of the sound re produced byeither one of the speakers while they are rotating is enhanced by reasonof the combined effect of the rotational movement of the speaker and theresonator mounting in which the speaker is supported.

2. In an apparatus for enhancing the tone quality of reproduced sound, acabinet, a shaft rotatably mounted in said cabinet, a resonator mountingsupported on said shaft to rotate with it, a speaker supported withinsaid resonator mounting so that the tone of the sound emanating fromsaid speaker is enhanced by the sympathetic vibration of said resonatormounting, and an amplifier connected to said speaker to energize it,whereby the tone quality of the sound reproduced by the speaker while itis rotated through a circle by revolving said shaft is enhanced byreason of the combined effect of the rotational movement of said speakerwith the resonator mounting in which the speaker is supported.

3. In an apparatus for imposing a vibrato effect upon reproduced sound,a cabinet, an electrically conductive shaft, an electrically conductiveadapter rigidly secured to one end of said shaft and electricallyinsulated therefrom, a bearing fixed to the top of said cabinet andadapted to receive said adapter for rotatably supporting one end of saidshaft while maintaining electrical conductivity with the rotatingadapter, a second bearing fixed to the bottom of said cabinet inalignment with said first bearing and adapted to receive the end of theshaft opposite the adapter for rotatably supporting it while maintainingelectrical conductivity with it so that the shaft is rotatably supportedby said bearings, a pair of speakers supported on said shaft in opposedrelationship to rotate with it, a jack fixed to each of said speakersand electrically connected therewith, a plug connected to said adapterand adapted to be inserted into either one of said speakers toelectrically connect the adapter with either one of the speakers, a pairof conductors, each electrically connecting one of the speakers with theshaft, and an amplifier having one of its output terminals connected tothe top bearing and the other to the bottom bearing, whereby either oneof said speakers may be individually energized by the amplifier while itis rotating by inserting said plug in either one of said jacks so thatone side of the circuit will be carried by one bearing and the adapterto the plug and speaker, and the other side of the circuit Will becarried by the shaft and the other bearing.

4. in an apparatus for imposing a vibrato effect upon reproduced sound,a cabinet, an electrically conductive shaft, an electrically conductiveadapter rigidly secured to one end of said shaft and electricallyinsulated therefrom, a bearing fixed to one end of said cabinet andadapted to receive said adapter for rotatably supporting one end of saidshaft while maintaining electrical conductivity with the rotatingadapter, a second bearing fixed to the other end of said cabinet inalignment with said first bearing and adapted to receive the end of theshaft opposite the adapter for rotatably supporting it while maintainingelectrical conductivity with it so that the shaft is rotatably supportedby said bearings, a pair of speakers supported on said shaft in opposedrelationship to rotate with it, an electrical conductor having one endconnected to the adapter and the other end connectable to either one ofthe speakers selectively for electrically connecting either one of thespeakers to the adapter, a

pair of conductors, each electrically connecting one of the speakerswith the shaft, and an amplifier having one of its output terminalsconnected to said first bearing and the other to said second bearing,whereby either one of said speakers may e individually energized by theamplifier while it is rotating by connecting said conductor with eitherone of the speakers so that one side 0 the circuit will be carried byone bearing and the to the speaker, and the other side of the circuitwill be carried by the shaft and the other bearing.

5. in an apparatus for imposing a vibrato effect upon reproduced sound,a cabinet, an electrically conductive shaft, an electrically conductiveadapter rigidly secured to one end of said shaft and electricallyinsulated there from, a bearing fixed to one end of said cabinet andadapted to receive said adapter for rotatably supporting one end of saidshaft while maintaining electrical conductivity with the rotatingadapter, a second bearing fixed to the other end of said cabinet inalignment with said first bearing and adapted to receive the end of theshaft opposite the adapter for rotatably supporting it while maintainingelectrical conductivity with it so that the shaft is rotatably supportedby said bearings, a speaker mounted on said shaft to rotate with it, anelectrical conductor connecting the adapter to the speaker forelectrically connecting the speaker to the adapter, a second electricalconductor electrically connecting the speaker with the shaft, and anamplifier having one of its output terminals connected to said firstbearing and the other to said second bearing, whereby one side of thecircuit will be carried by one bearing and the adapter to the speaker,and the other side of the circuit will be carried by the shaft and theother hearing so that the speaker may be energized by the amplifierWhile it is rotating with said shaft.

6. In an apparatus for enhancing the tone quality of reproduced sound, acabinet, a shaft having its ends tapered into a conical configuration, abearing fixed to the lower end of said cabinet and presenting a conicalrecess complementary to a tapered end of the shaft for receiving saidtapered end to rotatably support one end of the shaft, a bearing membersecured to the upper end of the cabinet and having a concentric bore inalignment with said lower bearing, a plug slidably disposed Within saidbore and presenting a conical recess complementary to a tapered end ofthe shaft for receiving it to rotatably support the other end of saidshaft, a spring disposed Within said here to yieldably urge said plugoutwardly of said bore into contact with its cooperating tapered end ofthe shaft so that the shaft may be readily removed from or assembledinto its position between said bearings by raising the shaft while inengagement with the conical recess of said plug against the force ofsaid spring to raise the lower end of the shaft above the lower hearingso that it may be displaced laterally into or out of engagement with thelower bearing, and a loud speaker mounted on said shaft to rotate withit and having electrical connection with an amplifier for energizing it,whereby the tone quality of the sound reproduced by the loud speaker maybe enhanced by rotating the shaft to cause a corresponding rotation ofthe speaker while it is reproducing the sound.

7. in an apparatus for enhancing the tone quality of reproduced sound, acabinet, a shaft having its ends tapered into a conical configuration, abearing fixed to the lower end of said cabinet and presenting a conicalrecess complementary to a tapered end of said shaft for receiving saidtapered end to rotatably support one end of the shaft, a bearing membersecured to the upper end of the cabinet and having a concentric bore inalignment with said lower bearing, a plug slidably disposed within saidbore and presenting a conical recess complementary to a tapered end ofthe shaft for receiving it to rotatably support the other end of saidshaft, a spring disposed within said bore to yieldably urge the plugoutwardly of said bore into contact with its cooperating tapered end ofthe shaft so that the shaft may be readily removed from or assembledinto its position between said hearings by raising the shaft while inengagement with the conical recess of said plug against the force ofsaid spring to raise the lower end of the shaft above the lower bearingso that it may be displaced laterally into or out of engagement with thelower bearing, a pair of disks fixed to said shaft in opposedrelationship, a peripheral flange fixed to each of said disks andextending from the disks in a direction away from said shaft, a pair ofcowls with each cowl having a front opening at one end and a rearopening at its opposite end, each of said cowls being supported by oneof said disks in concentric relationship therewith to extend outwardlyfrom the disk with its rear opening being adjacent to said disk andsoaced from the surface of said disk but being located within the areadefined by said flange so that said flange surrounds the end of saidcowl that is adjacent to the surface of said disk to form an annularopening between a portion of the surface of said cowl and'said flange, aloud speaker mounted within each of said cowls at the ends opposite thedisks so that the sound emanating therefrom may pass through the frontopening of the cowl and through said annular opening, and an amplifierconnectable to either one of said speakers selectively for individualenergization, whereby the tone quality of the sound reproduced by eitherone of the speakers while they are rotating is en hanced by reason ofthe combined effect of the rota tional movement of said speaker and thesympathetic vibration of said cowl and flanged disk.

8. In an apparatus for enhancing the tone quality of reproduced sound, acabinet, a shaft having its ends tapered into a conical configuration, abearing fixed to the lower end of said cabinet and presenting a conicalrecess complementary to a tapered end of said shaft for receiving saidtapered end to rotatably support one end of the shaft, a bearing membersecured to the upper end of the cabinet and having a concentric bore inalignment with said lower bearing, a plug slidably disposed within saidbore and presenting a conical recess complementary to a tapered end ofthe shaft for receiving it to rotatably support the other end of saidshaft, a spring disposed within said bore to yieldably urge the plugoutwardly of said bore into contact with its cooperating tapered end ofthe shaft so that the shaft may be readily removed from and assembledinto its position between said bearings by raising the shaft while inengagement with the conical recess of said plug against the force ofsaid spring to raise the lower end of the shaft above the lower bearingso that it may be displaced laterally into or out of engagement with thelower bearing, a resonator mounting supported on said shaft, a speakersupported within said resonator mounting so that the tone of the soundemanating from said speaker is enhanced by the sympathetic vibration ofsaid resonator mounting, and an amplifier connected to said speaker toenergize it, whereby the tone quality of the sound reproduced by thespeaker while it is rotated through a circle by revolving said shaft isenhanced by reason of the combined effect of the rotation movement ofthe speaker and the resonator mounting in which the speaker issupported.

9. in an apparatus for enhancing the quality of reproduced sound, acabinet, a shaft rotatably mounted in said cabinet, a pair of disksfixed to said shaft in opposed relationship, a peripheral flange fixedto each of said disks and extending from the disks in a direction awayfrom said shaft, a pair of cowls of substantially cylindricalconfiguration having a smaller diameter than the diameter of the circledefined by said flange with each cowl hazing from opening at one end anda rear opening at its opposite end, each of said cowls being supportedby one of said disks in concentric relationship therewith to extendoutwardly from the disk with its rear opening being adjacent to saiddisk and spaced from the surface said disk but being located within thearea defined by said flange so that said flange surrounds the end ofsaid cowl that is adjacent to the surface of said disk to form anannular opening between a portion of the surface of said cowl and saidflange, and a loud speaker mounted within each of said cowls at the endsopposite the disks so that the sound emanating therefrom may passthrough the front opening of the cowl and through said annular opening,whereby the tone quality of the sound reproduced by either one of thespeakers while they are rotating will be rendered more pleasant to thecar by reason of the combined effect of the rotational movement of thespeaker and the sympathetic vibration of said cowl and flanged disk.

l0. In an apparatus for enhancing the quality of reproduced sound, acabinet, a shaft rotatably mounted in said cabinet, a pair of disksfixed to said shaft in opposed relationship, a peripheral flange fixedto each of said disks and extending from the disks in a direction awayfrom said shaft, 21 pair of cowls with each cowl having a front openingat one end and a rear opening at its opposite end, each of said cowlsbeing supported by one of said disks in concentric relationshiptherewith to extend outwardly from the disk with its rear opening beingadjacent to said disk and spaced from the surface of said disk but beinglocated within the area defined by said flange so that said flangesurrounds the end of said cowl that is adjacent to the surface of saiddisk to form an annular opening between a portion of the surface of saidcowl and said flange, a loud speaker mounted within each of said cowlsat the ends opposite the disks so that the sound emanating therefrom maypass through the front opening of the cowl and through the annularopening, and an amplifier connectable to either one of said speakersselectively for individual energization, whereby the tone quality of thesound reproduced by either one of the speakers while they are rotatingis enhanced by reason of the combined effect of the rotational movementof the speaker and the resonance produced by said cowl and flanged disk.

11. In an apparatus for imposing a vibrato effect upon reproduced sound,a cabinet, a shaft rotatably mounted in said cabinet, a disk fixed tosaid shaft to rotate with it, a flange fixed to said disk and extendingfrom the disk in a direction away from said shaft, a cowl having a frontopening at one end and a rear opening at its opposite end and beingsupported by said disk in concentric relationship therewith to extendoutwardly from the disk with its rear opening being adjacent to saiddisk and spaced from the surface of said disk but being located withinthe area defined by said flange so that said flange surrounds the end ofsaid cowl that is adjacent to the surface of said disk to form anannular opening between a portion of the surface of said cowl and saidflange, and a loud speaker mounted within said cowl at the end oppositethe disk so that the sound emanating therefrom may pass through thefront opening of said cowl as well as through the rear opening of saidcowl and the annular opening, whereby the tone quality of the soundreproduced by the speaker while it is rotating with the shaft will berendered References Cited in the file of this patent UNITED STATESPATENTS Leslie Ian. 9, 1951 10 Myers Apr. 10, 1900 Hoch Feb. 25, 1930Kannenberg June 23, 1942 Mankowitz Dec. 20, 1949

